In U.S. Pat. No. 2,405,219, issued to Homer T. Lambert on Aug. 6, 1946, and assigned to Lambert Brake Corporation, of St. Joseph, Michigan, there is shown and described a brake disc that, after the completion of the usual machining operations required thereon, is split on radial lines into three sections after which sufficient material is removed at the severed ends of the sections to allow ample clearance between each pair of adjacent ends for expansion resulting from the generation of heat due to brake applications. This clearance between the adjacent ends of the several sections of the brake disc prevents the setting up of localized strains in the disc, which would cause warping or cracking of the disc.
When a disc is thus cut into sections, some means, such as tie-bolts and nuts, are required to secure the several sections together to form an annular braking disc, it being apparent that these securing means further increase the cost of the braking disc.
Accordingly, it is the general purpose of this invention to provide a one-piece metallic annular braking disc having novel means for preventing warping and cracking of the disc by the expansion of the metal resulting from the generation of heat produced by pressing braking elements against the respective opposite sides of the disc while a brake application is in effect.